Catheter Ablation | WPW Ablation

Key points:

Patients with Wolff-Parkinson-White syndrome (WPW) are at a very slightly increased risk of suffering dangerous disturbances of rhythm and radiofrequency ablation is often the recommended treatment

Radiofrequency ablation (cauterising procedure) is successful in 90-95% of patients in curing WPW

Although uncommon, complications occur in 2-3% of patients undergoing ablation

Treatment

There are a number of approaches to the treatment of supraventricular arrhythmias seen in patients with WPW.

General advice: Moderate alcohol and caffeine intake. This may help to reduce the frequency of attacks, but rarely leads to elimination of attacks.

Treating attacks: It is sometimes possible to treat episodes of palpitation by straining (the so-called Valsalva manoeuvre) or by applying very cold water to the face. If the attack does not terminate a visit to hospital allows a drug called adenosine to be given into a vein. This terminates the attack in a few seconds, although a transient feeling of shortness of breath and chest discomfort is usually experienced. This lasts less than ten seconds.

Drug treatment: A large number of medications may be used to either treat an acute episode or be taken regularly to try to prevent attacks. Simple drugs such as beta-blocking agents or calcium antagonists are often the first choice. They are usually well tolerated although beta-blockers in particular sometimes cause tiredness and should not be used in asthmatics. More powerful drugs are also available, such as flecainide and sotalol.

It should be noted that whilst drugs often provide a measure of arrhythmia control, it is unusual for total control of symptoms with drugs alone. Occasionally side effects may limit drug use, and, with the more powerful drugs, rarely the arrhythmia is exacerbated. In addition, as patients with WPW are at a slightly increased risk of dangerous arrhythmias, many doctors recommend catheter ablation as the best treatment, as described below:

Fine wires called catheters are passed into the heart through veins in the leg. These wires can stimulate (pace) the heart and also record electrical activity. Pacing the heart usually results in triggering of the arrhythmia, and electrical recordings allow the location of the extra pathway to be determined. Another catheter is introduced and positioned to the site of the extra pathway. This catheter delivers energy (usually radiofrequency) to the site of the extra pathway to cauterise and eliminate the arrhythmia. The success rate of the procedure is usually in excess of 90%.

Complications

Although the procedure is safe and effective in the large majority of patients there are small risks which must be considered before submitting to the treatment. These include the following:

Damage to vein(s) at the top of the leg. In approximately 1 in 500 cases a small operation is required to repair vein.

Cardiac perforation. In about 1 in 200 ablations a leak of blood occurs into the sac surrounding the heart. This causes a drop in blood pressure and is readily recognised and treated by inserting a small tube through the skin below the breast bone to drain the blood.

In about 60-70% of cases the extra pathway is located on the left side of the heart. Ablation in these cases carries an extremely small risk, approximately 1 in 1000, of blood clots forming which might result in a stroke.

In approximately 10-20% of cases the extra pathway is located in fairly close proximity to the normal electrical connections of the heart. Ablation carries a small risk of damaging the normal electrical wiring of the heart, resulting in a very slow heart beat. This is treated with an artificial pacemaker (see pacemaker section). The risk is usually no greater than one percent, but occasionally is as high as 3-5%, in which case your doctor may decide to use a different form of energy to freeze rather than burn away the extra pathway (cryoablation).

Recurrence of palpitations. In approximately 10% of cases the extra pathway 'comes back'. This does not mean a new pathway has grown, but that the pathway, only damaged by the ablation, has recovered. In these cases a repeat procedure is usually effective in curing the condition.

Your doctor will carefully discuss the procedure, including all the potential risks with you, and will obtain informed consent before starting.

Practical points about the procedure

Usually you will be asked to stop any cardiac medications you are taking to control the palpitations for about three days before coming into hospital.

The procedure takes about two to three hours and you will be required to lie fairly flat for about three hours afterwards to prevent any bleeding from the puncture sites at the top of your leg.

Most patients are discharged the following day feeling well. You may well have a little bruising at the top of your leg, and some patients feel a little sore in the chest. This usually resolves in a few days and simple analgesia with paracetomol may help.